Synthetic stucco compositions

ABSTRACT

The present invention relates to a synthetic antique-effect wall stucco for interiors and exteriors, with a smooth matt or translucent appearance, and its preparation process.

[0001] The present invention relates to a synthetic antique-effect wallstucco for interiors and exteriors, with a smooth matt or translucentappearance, and its preparation process.

BACKGROUND OF THE INVENTION

[0002] Synthetic stucco compositions have been known for some time, andall of them solve one or more of the problems associated with the use ofnatural stuccoes, which have been used for hundreds of years. U.S. Pat.No. 4,351,912, for example, relates to the manufacture of a light,spreadable synthetic stucco which contains light aggregates.

[0003] U.S. Pat. No. 4,563,491 relates to the manufacture of a syntheticstucco that incorporates a cooked flour paste which makes the productresistant to various environmental conditions, ultraviolet radiation,damp, salt water spray, fire and heat effects.

[0004] U.S. Pat. No. 6,515,062 discloses a method for obtaining adecorative synthetic stucco with a bright metallic appearanceconstituted by a synthetic stucco and approx. 200 mesh aluminium metalpigments. This stucco is distinguished from others by the“breathability” of the material, which eliminates the problemsassociated with bubble formation and condensation.

DISCLOSURE OF THE INVENTION

[0005] The present invention relates to an antique-effect syntheticstucco with a matt or translucent appearance.

[0006] The typical “antique effect” is produced by the specificcomposition of the product, and in particular by the choice of coatedfillers based on calcium carbonates, and the quantity ofmetal-oxide-based coloured inorganic pigments used.

[0007] At the application stage, this produces colour effects whichresemble decorative antique finishings.

[0008] The synthetic decorative stucco of the invention is characterisedby good water repellency due to the simultaneous participation ofacrylic polymer resins and mineral fillers based on calcium carbonates,coated with plasticising agents.

[0009] In view of the relative quantities of said two components thestucco exhibits hydrophobic behaviour, while at the same timemaintaining a fair degree of water vapour breathability.

DETAILED DESCRIPTION OF THE INVENTION

[0010] The synthetic stucco of the invention is characterised by coatedmineral fillers based on calcium carbonates and an acrylic resin inaqueous dispersion, together with conventional components of stucco suchas binders, pigments, dispersing, coalescing, anti-foaming and wettingagents, plasticisers, solvents and preservatives.

[0011] The fillers used in this invention are calcium carbonates with aparticle size not exceeding 10 μm, coated with a film of sodiumstearate, which are marketed under the brand name Master® and suppliedby Mineraria Sacilese S.p.a (Italy).

[0012] The polymer resins used in the invention include ethyl acrylatepolymers, polymers containing units of butyl acrylate, acrylic andmethacrylic acids and their esters. They are synthetic resins with a lowcontent of residual monomers (monomer residue less than 100 ppm) and amolecular weight of approx. 1,000,000 Daltons. These polymers arecommercially available, for example under the brand name Craymul 2222,supplied by Cray Valley S.r.l.

[0013] The calcium carbonate fillers are present in percentages rangingfrom 50 to 70% by weight, and preferably from 60 to 65%, while theacrylic resins in aqueous dispersion are present in the percentage ofbetween 15 and 25%, preferably between 18 and 23%, on the weight of thecomposition.

[0014] The binders used in the composition of the invention include, forexample, sodium carboxymethylcellulose, methyl hydroxyethyl cellulose,ethyl hydroxyethyl cellulose and the like, xanthan gum, gum arabic,polyvinyl alcohols, starch or a mixture thereof. Ethyl hydroxyethylcellulose is the preferred binder.

[0015] The various additives used for this invention, such as retardant,plasticising, coalescing, dispersing and anti-foaming agents,preservatives and solvents are conventional and easily available on themarket.

[0016] The coalescing agents are usually organic solvents which are usedto obtain a drier, less sticky film.

[0017] They are used to improve filming, which may be adversely affectedby various factors, especially low temperature, which prevents thepolymer particles from fusing together when the water has evaporated.The additives solve this problem because they act as solvent of thepolymer particles in dispersion, thus ensuring perfect fusion thereofeven at low temperatures.

[0018] The retardant agents considerably increase the drying time, andregulate water release by slowing it.

[0019] A problem with drying time arises in summer; the highertemperature causes the water to evaporate more quickly, and this factorhas an adverse effect because the plasterer does not have enough timefor the application and the product dries out, which makes it moredifficult to work with and considerably reduces its yield.

[0020] Furthermore, an excessively fast drying time would cause theproduct to lose its filmogenic characteristics.

[0021] The anti-foaming agent, which may be present even in smallpercentages, eliminates the foam formation caused when air is trapped inthe viscous mass of the product during stirring.

[0022] Aqueous dispersions of hydrophobic polymeric fatty acids andoxyethylenated derivatives in oxo-alcohols, or mixtures of hydrocarbonsand modified non-ionic fatty acids, can be used.

[0023] The wetting agents reduce the surface tension of the aqueoussolvent and thus, in synergy with the dispersing agents, if any, aidwetting of the pigments and the coated fillers.

[0024] The plasticising agents assist in giving the film greaterelasticity and resistance, producing films able to withstand dilationand microcracking of the walls to which they are applied.

[0025] The white pigments used for this invention are based on titaniumdioxide, while metal oxides such as iron, chromium, copper and the likeare used as coloured pigments.

[0026] A preferred composition of the synthetic stucco of the inventioncomprises: Water 11-14 parts by weight Ethyl hydroxyethyl cellulose0.28-0.40 linear-chain sodium polyphosphate 0.004-0.006 dispersing agent10-35% ammonia aqueous solution 0.01-0.05 Acrylic resin aqueousdispersion 18-23 Butyl glycol 0.25-0.40 Ethylene glycol 0.30-0.50Anti-foaming agent based on oxo-alcohols 0.15-0.25 and their derivativesWetting agent based on an aqueous solution of 0.20-0.35polyoxyethylenated and non-polyoxyethylenated surfactants Plasticiser(e.g. modified long-chain paraffin wax) 0.20-0.35 Coated calciumcarbonates 60.0-65.0 Preservative agent 0.10-0.20 Solvent - White spirit0.15-0.25 Titanium dioxide or metal oxides 2.8-3.5.

[0027] Preparation of the ready-to-use antique-effect synthetic stuccoaccording to the invention involves mixing the components such as water,cellulose, pH regulators, aqueous dispersions of acrylic esters,coalescing, retardant, anti-foaming, wetting and dispersing agents,plasticisers, preservatives, calcium carbonates and inorganic oxides.

[0028] The invention provides a translucent or matt synthetic stuccowith an antique effect which is white, or coloured due to the presenceof colouring pigments.

[0029] The stucco composition according to the invention allows easyapplication and less critical management of application times than atraditional lime-based stucco, as at least a 24-hour interval betweencoats is required at the temperature of 20° C.

[0030] The invention allows for the possibility of modifying theformulation of the product according to the period when it is applied,to take account of temperatures, for example.

[0031] The stucco composition according to the invention can be storedin plastic containers and transported to the place of use.

[0032] Before applying the stucco of the invention, it is sufficient tostir it manually with a trowel or a mechanical agitator to achieve goodhomogenisation, with no need to add water or solvents.

[0033] After opening of the container, any left-over product can bereused, even some time later, in view of the synthetic nature of thestucco, provided that contact with air is suitably prevented.

[0034] The stucco composition according to the invention has thefollowing advantages:

[0035] Particularly stable to atmospheric agents, UV rays and rapidchanges in temperature;

[0036] Characterised by good hydrophobia and a consequently low tendencyto absorb water;

[0037] Perfectly compatible with synthetically treated surfaces;

[0038] The ideal consistency due to the presence of acrylic copolymers;

[0039] Stability over time of colours and chromatic aspects.

[0040] The synthetic stucco of the invention can be applied in such away as to give a smooth, matt or translucent appearance which producesnumerous chromatic effects: if a matt appearance is required, a firstlayer of “paste” is laid on the surface to be treated, left to dry andsanded with abrasive paper, then a second very thin layer is laid andskimmed until a smooth surface is obtained.

[0041] To obtain a translucent appearance, when the second layer hasdried it is polished until a mirror finish is obtained.

EXAMPLE 1

[0042] Preparation of White Synthetic Stucco

[0043] 1. 5.10 Kg. Water

[0044] 2. 0.50 Kg. 10% linear chain sodium polyphosphate aqueoussolution.

[0045] 3. 8.00 Kg. 4% aqueous solution cellulose paste—Bermocoll ethylhydroxyethyl cellulose

[0046] 4. 0.05 Kg. 31.0% ammonia aqueous solution

[0047] 5. 20.0 Kg. Acrylic resin aqueous dispersion

[0048] 6. 0.35 Kg. Butyl glycol

[0049] 7. 0.40 Kg. Ethylene glycol

[0050] 8. 0.10 Kg. Anti-foaming agent—dispersion of fatty acids,hydrophobic polymers and oxyethylenated derivatives in oxo-alcohols

[0051] 9. 0.30 Kg. Wetting agent—aqueous solution of polyoxyethylenatedand non-polyoxyethylenated surfactants

[0052] 10. 0.30 Kg. Plasticiser—long-chain modified paraffin compounds

[0053] 11. 61.5 Kg. Calcium carbonates, dimensions approx. 10 μm, coatedwith sodium stearate

[0054] 12. 0.10 Kg. Anti-foaming agent—dispersion of fatty acids,hydrophobic polymers and oxyethylenated derivatives in oxo-alcohols

[0055] 13. 0.10 Kg. Preservative—solution of of urea-formaldehydecondensation products and isothiazolinone derivatives

[0056] 14. 0.20 Kg. White spirit

[0057] 15. 3.0 Kg. titanium dioxide white pigment

[0058] STEP 1. Place ingredients 1, 2, 3, 4, 6, 7 and 9 in aturbodisperser and stir energetically for 5 minutes.

[0059] STEP 2. Add ingredient 15 to the “paste” from STEP 1. Stir forapprox. 10 minutes until a homogenous composition is obtained.

[0060] STEP 3. Add ingredients 5, 8 and 10 to the “paste” from STEP 2and leave under stirring for approx. 2 minutes.

[0061] STEP 4. Add ingredient 11 and stir for approx. 15 minutes, untila lump-free material of uniform composition is obtained.

[0062] STEP 5. Add ingredients 12, 13 and 14 to the “paste” and stiruntil a homogenous product is obtained.

EXAMPLE 2

[0063] Preparation of Coloured Synthetic Stucco.

[0064] 1. 5.10 Kg. Water

[0065] 2. 0.50 Kg. 10% linear chain sodium polyphosphate aqueoussolution.

[0066] 3. 8.00 Kg. Cellulose paste in 4% aqueous solution—Bermocollethyl hydroxyethyl cellulose

[0067] 4. 0.05 Kg. 31.0% ammonia aqueous solution

[0068] 5. 20.0 Kg. Acrylic resin aqueous dispersion

[0069] 6. 0.35 Kg. Butyl glycol

[0070] 7. 0.40 Kg. Ethylene glycol

[0071] 8. 0.10 Kg. Anti-foaming agent—dispersion of fatty acids,hydrophobic polymers and oxyethylenated derivatives in oxo-alcohols

[0072] 9. 0.30 Kg. Wetting agent—aqueous solution of polyoxyethylenatedand non-polyoxyethylenated surfactants

[0073] 10. 0.30 Kg. Plasticiser—long-chain modified paraffin compounds

[0074] 11. 61.5 Kg. Calcium carbonate, dimensions approx. 10 μm, coatedwith sodium stearate

[0075] 12. 0.10 Kg. Anti-foaming agent—dispersion of fatty acids,hydrophobic polymers and oxyethylenated derivatives in oxo-alcohols

[0076] 13. 0.10 Kg. Preservative—solution of of urea-formaldehydecondensation products and isothiazolinone derivatives

[0077] 14. 0.20 Kg. White spirit

[0078] 15. 3.0 Kg. Inorganic pigments constituted by metal oxides

[0079] STEP 1. Place ingredients 1, 2, 3, 4, 6, 7 and 9 in aturbodisperser and stir energetically for 5 minutes.

[0080] STEP 2. Add ingredient 15 to the “paste” from STEP 1. Stir forapprox. 10 minutes, until a homogenous composition is obtained.

[0081] STEP 3. Add ingredients 5, 8 and 10 to the “paste” from STEP 2and leave under stirring for approx. 2 minutes.

[0082] STEP 4. Add ingredient 11 and stir for approx. 15 minutes, untila lump-free material of uniform composition is obtained.

[0083] STEP 5. Add ingredients 12, 13 and 14 to the “paste” and stiruntil a homogenous product is obtained.

1. A synthetic stucco composition with a smooth matt or translucentappearance and an antique effect.
 2. A composition as claimed in claim1, comprising calcium carbonate with a particle size not exceeding 10μm, coated with a film of sodium stearate, and an acrylic resin inaqueous dispersion.
 3. A composition as claimed in claim 2, wherein theacrylic resin comprises polymers of ethyl acrylate, butyl acrylate,acrylic and methacrylic acid and their esters, with a molecular weightof approx. 1,000,000 Daltons.
 4. A composition as claimed in claim 2,also comprising binders, pigments, dispersing, coalescing, anti-foamingand wetting agents, plasticisers, solvents and preservatives.
 5. Acomposition as claimed in claim 2, wherein the coated calcium carbonateis present in percentages ranging from 50 to 70% by weight, and theacrylic resins in aqueous dispersion are present in the percentage ofbetween 15 and 25%.
 6. A composition as claimed in claim 5, wherein thecoated calcium carbonate is present in percentages ranging from 60 to65% by weight, and the acrylic resins in aqueous dispersion are presentin the percentage of between 18 and 23%.
 7. A composition as claimed inclaim 6, having the following composition: Water 11.0-14.0% Ethylhydroxyethyl cellulose binder 0.28-0.40% in the range Linear chainsodium polyphosphate 0.004-0.006% dispersing agent 10-35% ammoniaaqueous solution 0.01-0.05% Acrylic resin aqueous dispersion 18-23%Butyl glycol 0.25-0.40% Ethylene glycol 0.30-0.50% Anti-foaming agentsbased on oxo-alcohols and 0.15-0.25% their derivatives Wetting agentbased on an aqueous solution of 0.200-0.35%  polyoxyethylenated andnon-polyoxyethylenated surfactants Modified long chain paraffin compound0.20-0.35% Calcium carbonate coated with sodium stearate 60.0-65.0%Preservative agent 0.100-0.200% White spirit 0.15-0.25% Pigments2.8-3.5%.


8. Composition as claimed in claim 7, wherein the pigments are titaniumdioxide or metal oxides.